Medical, especially surgical instruments relate, inter alia, to those instruments that are or can be equipped with motor-driven tools such as milling tools, drills, screwdrivers etc. The drive, for example for rotary or lifting motion of the tool, can be performed by an electric motor, hydraulically or pneumatically. Especially in the latter case, the instrument is connected to a compressed air source by means of which for example a turbine inside the instrument or as a separate motor unit is pressurized selectively and possibly controlled with compressed air, the rotation of the turbine then being transmitted directly or indirectly via a gear unit to the tool.
However, such pneumatically or hydraulically operated instruments are not permanently tightly connected to the pressurizing medium source but may arbitrarily be connected to or separated from the pressurizing medium source. For this purpose, clutches are required by means of which the instruments can be selectively connected pneumatically or hydraulically to the pressurizing medium source. Especially in surgical medicine, high requirements in terms of safety are made to said clutches so as to exclude injuries of patients and to facilitate handling of the instruments to the surgeon.
From the state of the art, medical, preferably surgical instrument systems comprising a pneumatic tool drive are known, as also the applicants in the present case have distributed them for years.
Such instrument systems usually include a pressurized medium source (to simplify matters, hereinafter referred to as pneumatic source) to which a preferably flexible pressure hose is or can be connected. At the downstream free end of the pressure hose there is preferably fixedly (i.e. permanently) mounted an operating handle configured as an actuating and/or control unit in the form of a handle at the distal free end of which in turn a clutch for a medical/surgical instrument is configured. The clutch takes over the mechanical connection between the handle and the selected instrument and, at the same time, the pneumatic connection of a pneumatic motor (e.g. turbine), which is internal to the instrument or separate, to a pneumatic actuating and/or control unit which is internal to the handle.
The actuating and/or control unit is composed of a manually operable actuator preferably in the form of an actuating lever pivoted on the handle and/or at least one press button, wherein the actuator mechanically acts directly or indirectly in a pneumatically/hydraulically pilot-controlled manner upon a regulating/control valve mechanism inside the handle which mechanism releases or inhibits a pneumatic connection to the instrument in response to the current actuating state. The release may be performed either according to the on-off principle or in a dosed manner corresponding to the degree of actuation of the actuator.
Since usually the handle is already connected to the pneumatic source and thus is pressurized before a selected instrument is coupled to the handle, there is basically the risk of the actuator being inadvertently actuated and, thus, of compressed air being allowed to escape in an uncontrolled manner. Moreover, there may arise the problem that, when the actuator is inadvertently actuated, the currently selected instrument is coupled which then is pressurized with compressed air and thus driven in an uncontrolled and inadvertent manner.
Therefore, in the known prior art at/within the handle a separate pneumatic safety lock is provided which after coupling the instrument and, resp., an upstream motor to the handle (and thus to the pressure hose—compressed air is applied) has to be manually enabled so as to release the function of the actuator. Such pneumatic safety lock may be, for example, an actuator latch which can be actuated by means of a slide supported on the preferably lever-shaped actuator so as to lock and/or unlock the actuator.
Although the afore-mentioned drawbacks and risks can be avoided by said additional pneumatic safety lock, handling of the instrument during surgical operation may possibly be complicated.